SAN DIEGO – A 92-year-old retired teacher who gained national attention for selling suicide kits for $40 was placed on five years of supervised probation on Monday for failing to file federal tax returns on her mail-order business.

Sharlotte Hydorn, a great-grandmother, pleaded guilty in December to a misdemeanor charge of failing to file federal income tax returns from 2007 through 2010, a period during which investigators said at least seven customers used her kits to kill themselves.

Prosecutors said Hydorn sold about 1,300 of the do-it-yourself asphyxiation hoods during those years but agreed to stop making or selling the kits as part of her plea deal. She was sentenced by a federal judge in San Diego. She was also ordered to pay a fine of $1,000.

Hydorn said after sentencing that all she wanted to do was allow people to die at home, surrounded by family and friends.

'Agonizing pain'A Spokane, Wash., native, Hydorn began assisting physicians with patient suicides after her husband, Rex, died of colon cancer in 1977, said Charles Goldberg, her lawyer. Her husband had been in "agonizing pain" and did not want to die "filled with tubes in a hospital," she said.

Hydorn felt she could design a helium hood that would be more comfortable for patients than the ones she saw doctors using. She received "thousands" of orders for her hoods and began charging for her time and materials. Hydorn's kits included tubing, material for the hood and a user diagram. A helium source was not included.

Agents who raided her home in suburban San Diego last year found checks that were not cashed and thousands of dollars in cash from buyers, Goldberg said.

Prosecutors said she took no steps to verify the physical condition, age, identity or mental state of her customers and therefore had no idea whether her kits were being bought by people suffering from depression or by minors acting without the consent of an adult. Court documents say she sold more than 1,300 kits to people across the United States and abroad. Most of them contacted her by mail or phone.

Hydorn had pleaded guilty to the tax charge dating back to 2007 and acknowledged she made more than $150,000 in income from various sources during that period, including from the sale of helium kits.

Hydorn said she sold the kits under the name "GLADD Group." In court, she admitted she made $66,717 in 2010 and paid no taxes on that.

NBCSanDiego.com, The Associated Press and Reuters contributed to this report.